This invention relates to DC to AC inverter circuits and, more particularly, to inverter circuits capable of providing AC power to loads having various impedance characteristics.
Full wave DC to AC inverter circuits are known. One such circuit, having two SCR inverter switches and operating into the center tapped primary winding of a transformer, is illustrated in the General Electric SCR Manual, Third Edition, copyright 1964, FIG. 9.2.5, page 161. Each of the inverter SCR's is alternately turned on by timing signals. Self-commutating circuitry is relied on to turn off the conducting SCR switch when the other is turned on. The self-commutating circuitry does not perform reliably, and both inverter switches sometimes conduct at the same time.
A principal feature of this invention is the provision of a full wave inverter having a positively acting commutating circuit which ensures shut-off of the appropriate SCR inverting switch. Pulse circuits provide gate pulses which alternately actuate each of the inverter switches and commutation trigger circuits control the discharge of the commutating capacitor across the SCR inverting switches.
Another feature of the invention is that a single commutating capacitor is connected to both inverter switches and is charged during conduction of the switch with an amount of energy that is directly related to the load on the inverter.
A further feature is that the system is light in weight because the number of transformers and capacitors is minimized.
Further features and advantages of the invention will be readily apparent from the following specification and from the drawings.